Sat, 17 Jun 95 10:59:21 +0100

Dear Drs Maignan, Bonfand and Gosselin

I very much enjoyed reading your poster contribution number 31 to the ECTOC
conference. One of the important aspects of your work is the ability
directly to effect alpha-deprotonation of p-tolylsulfinylethene and to
carry out reactions of the resulting anions with electrophiles. Is this a
general process? What other electrophiles work well in these reactions?
Do you see any asymmetric induction with additions to aldehydes? Do
epoxides work?

I was interested also to read some of your own, cited work (Tetrahedron:
Asymmetry, 1994, 5, 781, and Tetrahedron Letters. 1992, 33, 2347)
concerning other sulfinyldienes, particularly
2-(p-tolylsulfinyl)-3-(trimethylsilyloxy)-1,3-butadiene. In 1989, we
synthesised the homologous compound
exclusively as the E-isomer, but tried without success to effect
Diels-Alder reactions with electron-deficient dienophiles. I feel sure
that our problem was one of unfavourable cisoid conformation: the X-ray
structure showed that the material crystallised in the transoid form. We
tried unsuccessfully to make
2-(p-tolylsulfinyl)-3-(trimethylsilyloxy)-1,3-butadiene; I would be
extremely interested to know whether it (or its TBDMS analogue, which might
overcome the hydrolytic sensitivity problems you describe) is effective in
Diels-Alder reactions.

With best wishes.

Donald Craig

Dr D Craig
Dept of Chemistry
Imperial College of Science, Technology and Medicine
London SW7 2AY

tel +44 (0)171-594 5771
fax +44 (0)171-594 5804

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